Vertical power transistors, such as group IV based trench type field-effect transistors (trench FETs), are used in a variety of applications. For example, silicon based trench metal-oxide-semiconductor FETs (trench MOSFETs) may be used to implement a power converter, such as a synchronous rectifier, or a direct current (DC) to DC power converter.
For many trench MOSFET applications in which high switching speeds are necessary or desirable, it is advantageous to reduce gate charge so as to reduce switching loss. In addition, as the electronic devices and systems utilizing power MOSFETs are continually reduced in size, there is a corresponding need to reduce the size of the MOSFETs themselves. However, the resulting reduction in cell pitch and increased power density tends to undesirably increase gate charge in conventional trench MOSFET structures.